This description relates to color gamut mapping.
Color gamut refers to the range of colors that can be reproduced by a medium or processed by a device. Color gamut mapping is useful in processing color data of images that are reproduced in different media or processed by different devices. The color gamut of an image can be compressed or expanded. For example, an image recorded on a color slide film may have colors outside the range of colors that can be shown on a liquid crystal display. To show such an image on the display, some of the colors will have to be clipped or compressed. On the other hand, the color gamut of a dull photo can be expanded to have brighter and more vivid colors.
In one example, a color gamut can be represented as a volume in a color space that uses a cylindrical coordinate system. Each point in the volume represents a color, and the coordinates (height, radius, and azimuthal angle) of the point represent the luminance (L), chroma (C), and hue (H), respectively, of the color. The surface of the volume represents the color gamut boundary, indicating the outer range of the color gamut.
The color gamut of a first medium or device can be represented as a first volume in the color space. The color gamut of a second medium or device can be represented as a second volume in the color space. Color gamut mapping involves mapping (or converting) coordinates of points in the first volume to coordinates of points in the second volume. The human eye is typically more sensitive to changes in hue. One method of gamut mapping is performed by preserving perceived or actual hue values while changing the luminance and/or chroma values.